Tectonic evolution of Proterozoic-Jurassic in six provinces of southeastern China

Abstract

Based on the principle of combining historic analysis with mechanical analysis, the deformation characteristics, stress orientations and distributions of four main tectonic events from the Proterozoic to the Jurassic are discussed. In the late Proterozoic (the Jinningian event), a series of isoclinal folds with east-west orientated axis were formed by north-south compression, drawing together the Sino-Korean Terrane to the Yangtze-Jiangnan and South China Terranes. In the early Paleozoic (the Caledonian event), a fold system with an almost north-south trending axis and associated with migmatization occurred in the South China Terrane, which obviously had suffered from nearly east-west orientated compression. However, in the Yangtze-Jiangnan and Sino-Korean Terranes, only some unconformities are found in the Paleozoic group. In the Triassic (the Indosinian event), collision and subduction occurred, involving the Sino-Korean, Yangtze, Jiangnan and South China Terranes, leading to widespread development of the fold system with an approximately east-west orientation and some granitic intrusions. This movement took place earlier and was stronger in the south than in the north. In the Jurassic (the Yanshanian event which was characterized by W.N.W.-E.S.E. trending compression), a series of N.E.-N.N.E. trending thrusts and folds were formed.